Simon Pegg and Nick Frost (Hot Fuzz, Shaun of the Dead) reunite for the comedy adventure Paul as two sci-fi geeks whose pilgrimage takes them to America's UFO heartland. While there, they accidentally meet an alien who brings them on an insane road trip that alters their universe forever. For the past 60 years, an alien named Paul (voiced by Seth Rogen) has been hanging out at a top-secret military base. For reasons unknown, the space-traveling smart ass decides to escape the compound and hop on the first vehicle out of town-a rented RV containing Earthlings Graeme Willy (Pegg) and Clive Gollings (Frost). Chased by federal agents and the fanatical father of a young woman that they accidentally kidnap, Graeme and Clive hatch a fumbling escape plan to return Paul to his mother ship. And as two nerds struggle to help, one little green man might just take his fellow outcasts from misfits to intergalactic heroes...

In order to decide if you would like “Paul”, a science-fiction comedy from Simon Pegg and Nick Frost, you should probably ask yourself this: “Am I a nerd?”

This is not to say that the movie’s sense of humor is solely geared to those with categorical memories of “Star Wars” films and comic-book history. But you will probably notice that those guys are laughing a lot more in the theater than anyone else. Like I was.

Pegg and Frost have a penchant for making likable and well-paced English satire aimed squarely at pop-culture. In 2004, they starred together in the zombie parody “Shaun of the Dead”, which Pegg co-wrote with director Edgar Wright. Three years later, the trio took on the action film genre with “Hot Fuzz”, loading their film with unaccredited cameos while parodying the absurdist nature of these types of movies.

Their style of comedy makes fun of that which already makes fun of itself. At no point does their sense of humor seem cruel or harmful regarding the source material (in this case, alien flicks). Much like Kevin Smith’s loquacious comedies, the overall humor is friendly and socially engaging. With Pegg and Frost’s energetic script, the characters ramble throughout this story and we are never bored by their inane and ridiculous banter.

But there are some physical gags played out by the live actors, as well as the movie’s animated and titular alien. Some of these jokes go pretty far to get that laugh, and it almost seems like these are for the kids. But once we hear Kristen Wiig say “fat, hairy cock”, we remember that this one is rated R and wonder, “what kids?”

The script was written by Pegg and Frost, who play science-fiction nerds Graeme (pronounced “Graham”) and Clive, respectfully. Joining them is a cast of today’s best and brightest comedians: Kristin Wiig as a Creationist love interest; Jason Bateman as a stealth government agent; Bill Hader as a bumbling Federal underling; and Seth Rogen as the voice of Paul.

Paul is an alien fugitive who has been stuck in federal custody for the past sixty years when his spaceship crash-landed on Earth n 1947. This element of the storyline provides some of the movie’s best lines.

Remembering his contributions to pop-culture, Paul flashbacks to a phone conversation he had in 1980 with Steven Spielberg. Yes, that is actually Mr. Spielberg’s voice on the other line.

The celebrated director’s appearance in “Paul” is an example of Hollywood’s affection for smart English humor poking fun at American paranoia and bigotry. Check out Ricky Gervais’ underrated “The Invention of Lying” and count the number of A-list celebrities making quick yet unforgettable cameos.

The plot structure is simple and perfectly matched for the racy dialogue. While traveling through America after attending Comic-Con in San Diego, Graeme and Clive discover Paul after he crashes a stolen car in the middle of the desert highway. He explains he is on the run. And from there, the movie becomes an active chase sequence as the group escapes the FBI, a pair of homophobic hunters, and an overprotective father named Moses (John Carroll Lynch).

All of the actors, principals and cameos combined, handle the material with expert timing and performance. Pegg and Frost understand the material intimately not just because they wrote it, but because they actually enjoyed it. In fact, they both went on a personal road trip together across America during the pre-production phase to discover useful ideas for their script. That is honest writing. And it is a shame there is not more of that kind of dedication in today’s comedies.

Wiig is typically hysterical as the potty-mouthed Christian who sees the light of futility when she meets Paul. Bateman has some great lines, which he delivers in perfect deadpan as the no-nonsense Special Agent Lorenzo Zoil (say it out loud). And America’s favorite lesbian Jane Lynch takes a break from “Glee” to provide some color as a stern roadside waitress.

The only one who seems out of step among the ensemble cast is, well, Paul. Seth Rogen gives the character an easy-going and agreeable persona, such as that Paul could easily be a character from a Judd Apatow movie. And the animation department was wise in depicting Paul as if he was an outcast from “Close Encounters of the Third Kind”. But with Rogen’s gruff delivery coming from the alien’s meek green face, it is hard to forget that the guy who “Knocked Up” Katherine Heigl is the voice of the titular alien. In other words, it’s a hard sell.

But this is sincerely the most fun I have had in a comedy in a long time. Be warned though that many of the jokes are based on references from celebrated and obscure moments in science-fiction fantasy. As the characters quote lines from “Aliens” and “Star Wars”, I could not help but notice that I was the only one laughing out loud at these allusions. Then again, I am a total nerd.